1. Field of the Invention
The present invention relates to an integrated cast and muscle stimulation system, and more particularly, it relates to a treatment electrode device that provides electric stimulation to an anatomical site that is covered by a cast.
2. Description of Related Art
Injuries to the musculoskeletal system (bones, joints, muscles, ligaments, tendons) or conditions like arthritis, and osteoporosis are the leading reason for patient visits to physicians"" offices. Sprains or dislocations and fractures account for almost half of all musculoskeletal injuries. Fractures can occur in a number of ways. Most fractures are the result of trauma (e.g., falls, car accidents). Osteoporosis, a bone disease, makes bones fragile and easily broken. Overuse can result in stress fractures, which are common among athletes. Physicians treat fractures with plaster casts, fiberglass casts, cast-braces, splints, pins or other devices to hold the fracture in the correct position while the bone is healing. Depending on the extent of the injury a fracture can take from several weeks to several months to heal.
Fractures are painful, but the pain usually stops long before the fracture is strong enough to handle normal activity. Usually, when the bone is healed the muscles are weak from lack of use. A period of rehabilitation is necessary for function to return to normal and healing to be complete. Today, amazing results are being seen in the treatment of bone fractures and other bone diseases with the use of electrical stimulation.
In U.S. Pat. No. 4,583,550, issued Apr. 22, 1986, an invention is described which incorporates a covered access window into a conventional plaster cast. An electrode can be applied through the access window. This invention is limited in size/shape of the electrode. Also, the invention is described for use with conventional plaster casts.
There are disadvantages to any kind of xe2x80x9cwindowingxe2x80x9d in a cast. While cast saws are generally quite safe, it is still possible for abrasions to occur during the procedure. The cutting away of an area on a harden cast can also result in structural weakness to the cast. It is often desirable to apply an electrode directly to the fracture site, which is also the least desirable place to cut a window into a cast.
In U.S. Pat. No. 4,535,779, issued Aug. 20, 1985, a device is described which incorporates a flange and collar assembly into a cast. The flange and collar assembly can be attached to an external electric stimulator. This invention is labor intensive as well as physically limiting to the patient when the electric stimulator is attached to the cast.
Therefore, there is a need for an improved device and method for applying electrical stimulation to an anatomical site, which is covered by a cast. The present invention provides a new and improved device for integrating a treatment electrode in a body cast. The invention is simple in construction, use, and maintains the structural integrity of the cast while permitting reliable electrical stimulation.
An object of the present invention is to provide a device and method for applying a treatment electrode to an anatomical site covered by a cast.
These and other objects will be apparent to those skilled in the art based on the teachings herein. Other objects and advantages of the present invention will become apparent from the following description and accompanying drawings.
The invention integrates a treatment electrode into a cast. The cast is molded around the limb to immobilize the fracture. Replaceable electrodes are positioned over the peripheral nerves of the musculature surrounding the fracture site and an electrical stimulation unit applies voltage pulses to the electrodes through buried electrical conductors. A variety of electrical pulse formats can be used to achieve a desired result.
An exemplary description is provided for treating a patient with the present invention. The electrodes are inserted into a port that is placed within the cast during the cast building phase. The physician first winds a layer of soft material 50 around the limb. A port structure is then placed at the appropriate anatomical site for stimulation. An electrical stimulation unit is inserted into the port and electrical pulses are applied to the nerves underlying the electrodes.
An alternative method for integrating the port with the cast is provided. In this embodiment, the port structure has an outer segment that perforates the cast outer layers as they are wound around the affected area. After the cast has dried and set the outer segment is cut or snapped off exposing the port.
In an alternative embodiment the port structure is integrated with a soft material bottom layer that has a central hole. This embodiment would be applied to the skin before the soft material layer 50 is wound over the skin. The advantage of this approach is that it eliminates the need for pulling out or cutting out the soft material within the port aperture to expose the skin.
The electrode port structure allows the placement of both an electrode module and a restraint module. In order to prevent skin from herniating into the port, either an electrode module or restraint module should be placed within the port at all times.
The electrode module consists of a conductive layer that enables current to flow from the stimulator into the tissue. An electrical conductor connects the conductive layer to a conductive pad that makes contact with conductors when the electrode module is inserted into the port.
The restraint module is designed to have a total thickness that is comparable to the cast and port assembly. The bottom layer of the restraint module is made of a soft material. A flip top actuates pegs that lock into peg holes to hold the restraint module in place. An alternate o-ring design is provided for securing the restraint module.